1nht: Difference between revisions
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==Overview== | ==Overview== | ||
Crystal structures of adenylosuccinate synthetase from Escherichia coli | Crystal structures of adenylosuccinate synthetase from Escherichia coli complexed with Mg2+, 6-thiophosphoryl-IMP, GDP, and hadacidin at 298 and 100 K have been refined to R-factors of 0.171 and 0.206 against data to 2.8 and 2.5 A resolution, respectively. Interactions of GDP, Mg2+ and hadacidin are similar to those observed for the same ligands in the complex of IMP, GDP, NO3-, Mg2+ and hadacidin (Poland, B. W., Fromm, H. J. & Honzatko, R. B. (1996). J. Mol. Biol. 264, 1013-1027). Although crystals were grown from solutions containing 6-mercapto-IMP and GTP, the electron density at the active site is consistent with 6-thiophosphoryl-IMP and GDP. Asp-13 and Gln-224 probably work in concert to stabilize the 6-thioanion of 6-mercapto-IMP, which in turn is the nucleophile in the displacement of GDP from the gamma-phosphate of GTP. Once formed, 6-thiophosphoryl-IMP is stable in the active site of the enzyme under the conditions of the structural investigation. The direct observation of 6-thiophosphoryl-IMP in the active site is consistent with the putative generation of 6-phosphoryl-IMP along the reaction pathway of the synthetase. | ||
==About this Structure== | ==About this Structure== | ||
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[[Category: Escherichia coli]] | [[Category: Escherichia coli]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
[[Category: Bruns, C | [[Category: Bruns, C A.]] | ||
[[Category: Fromm, H | [[Category: Fromm, H J.]] | ||
[[Category: Honzatko, R | [[Category: Honzatko, R B.]] | ||
[[Category: Poland, B | [[Category: Poland, B W.]] | ||
[[Category: GDP]] | [[Category: GDP]] | ||
[[Category: HAD]] | [[Category: HAD]] | ||
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[[Category: x-ray crystallography]] | [[Category: x-ray crystallography]] | ||
''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 14:06:16 2008'' | ||
Revision as of 15:06, 21 February 2008
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ENTRAPMENT OF 6-THIOPHOSPHORYL-IMP IN THE ACTIVE SITE OF CRYSTALLINE ADENYLOSUCCINATE SYNTHETASE FROM ESCHERICHIA COLI DATA COLLECTED AT 100K
OverviewOverview
Crystal structures of adenylosuccinate synthetase from Escherichia coli complexed with Mg2+, 6-thiophosphoryl-IMP, GDP, and hadacidin at 298 and 100 K have been refined to R-factors of 0.171 and 0.206 against data to 2.8 and 2.5 A resolution, respectively. Interactions of GDP, Mg2+ and hadacidin are similar to those observed for the same ligands in the complex of IMP, GDP, NO3-, Mg2+ and hadacidin (Poland, B. W., Fromm, H. J. & Honzatko, R. B. (1996). J. Mol. Biol. 264, 1013-1027). Although crystals were grown from solutions containing 6-mercapto-IMP and GTP, the electron density at the active site is consistent with 6-thiophosphoryl-IMP and GDP. Asp-13 and Gln-224 probably work in concert to stabilize the 6-thioanion of 6-mercapto-IMP, which in turn is the nucleophile in the displacement of GDP from the gamma-phosphate of GTP. Once formed, 6-thiophosphoryl-IMP is stable in the active site of the enzyme under the conditions of the structural investigation. The direct observation of 6-thiophosphoryl-IMP in the active site is consistent with the putative generation of 6-phosphoryl-IMP along the reaction pathway of the synthetase.
About this StructureAbout this Structure
1NHT is a Single protein structure of sequence from Escherichia coli with , , and as ligands. Active as Adenylosuccinate synthase, with EC number 6.3.4.4 Known structural/functional Sites: , and . Full crystallographic information is available from OCA.
ReferenceReference
Entrapment of 6-thiophosphoryl-IMP in the active site of crystalline adenylosuccinate synthetase from Escherichia coli., Poland BW, Bruns C, Fromm HJ, Honzatko RB, J Biol Chem. 1997 Jun 13;272(24):15200-5. PMID:9182542
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